The present invention relates generally to the manufacture of small electronic components and, more particularly, to a structure and process of encapsulating the components and to the production of an associated carrier structure for testing and transporting the electrical components.
Electronic components, especially semiconductor devices such as transistors and integrated circuits, have been encapsulated in plastic in the past. For example, U.S. Pat. No. 3,716,764, issued to R. O. Birchler, et al., describes the standard encapsulation techniques for the TO-92 package. Similarly, other standard plastic packages have been developed and are in wide-spread use in the electronics industry.
However, a common problem associated with electronic components is providing a suitable means of handling these components without damage for purposes of testing, marking, and shipment. This is especially true of package types which are small and have fragile leads. They are characterized by a molded plastic body in the form of a small rectangular bar constructed to protect and hold the semiconductor die and wire bonds and to also hold the three package leads in place. The metal tabs extending from the body are flat and thin and must be precisely formed so as to form a flat bonding surface which lies just below the bottom surface of the body. As a result, the leads associated with this device are fragile and easily bent.
In the past, these types of packages with fragile leads have been protected by utilizing special carriers designed for this purpose. While these carriers are necessary for the protection of the device, they have several undesirable features. First, there is the initial expense in buying the carriers. Also, since the semiconductor chip itself is fairly inexpensive, the cost of the carrier becomes a significant part of the cost of the delivered product. Secondly, there is additional money and time expended in the process of loading each device into each carrier and removing the device again prior to insertion into the circuit. Thus, it can be appreciated that some sort of protective means which does not involve a separate carrier is highly desirable.
Accordingly, it is an object of this invention to provide inexpensive yet convenient carrier package for electronic components.
It is also an object of this invention to construct a carrier structure which requires no additional labor to produce the carrier above the labor necessary to encapsulate the electronic component.
It is still another object of this invention to provide a carrier structure which does not put any stresses on the device leads during handling and shipment.
It is also an object of this invention to use some of the plastic which would normally be discarded as the carrier structure for electronic components.
It is still another object of this invention to provide a method whereby a carrier structure holds the electronic component with plastic tabs allowing easy separation of a component and the carrier.
It is still another object of this invention to provide a carrier which will protect precisely formed leads of the electronic component from being damaged during testing, marking, shipping, or other handling.
It is still another object of this invention to provide an asymmetric carrier package which can be bowl fed into an automatic component loading mechanism rather than requiring that the electronic components to be loaded into a component magazine for later automatic insertion into an electronic circuit.